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Natural Resources — quick quiz

5 SZF IOS-pattern questions on Natural Resources. Instant scoring and solutions, no signup — see where you stand in a few minutes.

Question 1 of 5

Hard

A city discharges untreated sewage into a river. Scientists measured dissolved oxygen levels at different points: 8 mg/L upstream (before discharge point), 2 mg/L at the discharge point, and 4 mg/L several kilometers downstream. Fish were found dead near the discharge point. Which of the following BEST explains the pattern of oxygen levels and fish deaths?